Device for changing the work rolls and the back-up rolls of a strip-mill

ABSTRACT

The invention relates to a method and a device for changing the work rolls and the back-up rolls ( 8, 9 ) of a strip mill, by means of a roll-changing carriage ( 2 ) which can be transversally displaced in relation to the roll stand ( 1 ). Said roll-changing carriage receives the old sets of rolls removed, enabling them to be exchanged for new sets of rolls.

The invention concerns equipment for changing the work rolls and backup rolls of a strip mill by means of a roll-changing carriage that moves transversely to the roll stand and receives the extracted old sets of rolls and replaces them with new sets of rolls.

A wide variety of different types of equipment for changing rolls is already known, and roll-changing carriages are also already being used. An example of this is DE 39 30 125 C2.

In general, the previously known changing equipment has the disadvantage that the constructional expense for setting up the equipment is very high, especially because significant foundation adaptations are often necessary. Another disadvantage is that the necessary cylinders and hydraulic motors often must be supplied with energy via cable draglines, which is relatively expensive.

The objective of the present invention is to refine the equipment in such a way that it can not only change the backup rolls, but can also change the work rolls with the same cylinder used to change the backup rolls.

In accordance with the invention, this objective is achieved with the features of claim 1. In particular,

-   -   a stationary changing cylinder is mounted at mill floor level,         whose piston rod can be run in and out transversely to the roll         stand,     -   an extraction carriage, which is installed at the forward end of         the piston rod of the changing cylinder, can be moved on the         roll-changing carriage and can be coupled with the roll-changing         carriage in such a way that the extraction carriage, together         with the roll-changing carriage, can be moved by the changing         cylinder transversely to the roll stand,     -   and a transverse shift table, which is installed in the         roll-changing carriage, can be shifted by a shift cylinder that         is independent of the roll-changing carriage transversely to the         direction of movement of the roll-changing carriage, and can         bring the sets of rolls to be changed into or out of the         changing position aligned with the middle of the stand.

This solution in accordance with the invention has a number of advantages. For example, all of the cylinders are arranged in such a way that stationary piping is possible. This eliminates the cable draglines that would otherwise be necessary. Only three cylinder units are now necessary, specifically, for the roll-changing cylinder, the transverse shift table, and the locking equipment. Since the changing cylinder lies above the mill floor, hardly any foundation work is necessary. This and the simple and lighter type of construction of the entire changing equipment made it possible to reduce costs.

Finally, it should also be noted that the more easily accessible stationary cylinder units facilitate maintenance work.

The roll-changing carriage is initially in the standby position shown in FIG. 1. In this position, the roll-changing carriage 2 is positioned below the changing cylinder 4, which is shown with the piston rod 5 retracted. A prepared set of new rolls is located on the transverse shift table 6 next to the changing cylinder 4. An extraction carriage 3 is located at the forward end of the piston rod 5. As FIG. 2 shows, the extraction carriage, together with the roll-changing carriage 2, is moved by the piston rod towards the roll stand and automatically couples with the old set of work rolls 8. The connection between the extraction carriage 3 and the roll-changing carriage 2 is then broken, and at the same time the roll-changing carriage 2 is locked by the transverse shift cylinder 7 (FIG. 3). The extraction carriage can then pull back the old set of rolls onto the transverse shift table 6 by means of the changing cylinder 4. On the transverse shift table 6, suitable transverse shifting by the transverse shift cylinder 7 brings the old set of work rolls out of position and the new set of work rolls into position (FIG. 4), and then the new set of work rolls can be run into the stand, as is shown in FIGS. 5 and 6.

FIGS. 7 and 8 show the return to the starting point, i.e., the standby position of the roll-changing carriage 2.

If one wishes to change the backup rolls as well, the installation of the new set of work rolls is deferred, and the extraction carriage 3 first extracts the lower backup roll 9 from the roll stand. To do this, this backup roll is moved transversely to the roll stand on rails, which are located below the level of the mill floor (FIGS. 1′ and 2′).

In a changing position to the side of the stand, a dummy is then placed on the lower backup roll (FIG. 3′). The dummy is then moved back into the roll stand to pick up the upper backup roll (FIG. 4′). Both backup rolls are then brought back to the changing position provided to the side of the roll stand, where a crane is used to take away the old set of rolls and bring up the new set of rolls. FIGS. 5′ to 16′ show the remainder of the installation operation, which is the reverse of the removal operation, and the return of the roll-changing carriage 2 to the standby position or starting point. 

1.-3. (canceled)
 4. An apparatus for changing the work rolls and backup rolls of a roll stand in a strip mill, the strip mill defining a longitudinal path therethrough, said apparatus comprising: a roll-changing carriage movable transversely to the longitudinal path of the strip mill, said roll-changing carriage being movable from a distal standby position to a proximal position relative to the roll stand; a stationary changing cylinder mounted proximate a floor level of the strip mill and a piston movably inserted in said changing cylinder and having a forward end projecting out of said changing cylinder, said piston being movable in said changing cylinder transverse to the longitudinal path of the strip mill; an extraction carriage connected to said piston rod at said forward end and movable with said piston rod on said roll-changing carriage, said extraction carriage being selectively connectable with said roll-changing carriage such that said extraction carriage and said roll-changing carriage are movable together by said piston rod of said changing cylinder transversely to the longitudinal path of said strip mill when said extraction carriage is connected with said roll-changing carriage; a transverse shift table installed on said roll-changing carriage and movable approximately parallel to the longitudinal path of the strip mill; and a shift cylinder movable approximately parallel to the longitudinal path of said strip mill and selectively engageable with said transverse shift table for moving said transverse shift table into and out of a changing position aligned with the roll stand.
 5. A process for changing work rolls in a roll stand of a strip mill using the apparatus of claim 1, comprising the steps of: arranging the roll-changing carriage at the distal standby position, wherein the transverse table holds a new set of work rolls; coupling the extraction carriage to the roll-changing carriage and moving, by the changing cylinder, the extraction carriage and the roll-changing carriage to the proximal position relative to the roll stand; connecting the extraction carriage with an old set of work rolls in the roll stand to be changed; uncoupling the extraction carriage from the roll-changing carriage and engaging the transverse shift table with the shift cylinder, which causes the roll-changing carriage to be locked in the proximal position relative to the roll stand; moving, by the changing cylinder and the extraction carriage, the old set of work rolls from the roll stand to a changing position on the transverse shift table; disconnecting the extraction carriage from the old set of work rolls; shifting the transverse shift table, by the shift cylinder, so that the old set of work rolls is moved out of the changing position and the new set of work rolls is moved into the changing position, which is aligned with the roll stand; connecting the extraction carriage with the new set of work rolls and moving, by the changing cylinder, the extraction carriage and the new set of work rolls such that the new set of work rolls are moved into the roll stand; disconnecting the extraction carriage from the new set of work rolls; disengaging the shift cylinder from the transverse shift table and coupling the extraction carriage to the roll-changing carriage; and moving the roll-changing carriage with the old set of work rolls located on the transverse shift table into the distal standby position, where the old set of work rolls is removeable.
 6. A process for changing the backup rolls in a roll stand of a strip mill after removal of the work rolls using the apparatus of claim 1, comprising the steps: arranging the roll-changing carriage at the distal standby position; coupling the extraction carriage to the roll-changing carriage and moving, by the changing cylinder, the extraction carriage and the roll-changing carriage to the proximal position relative to the roll stand; connecting the extraction carriage with a lower backup roll of the old set of backup rolls in the roll stand to be changed; moving, by the changing cylinder, the extraction carriage and the roll-changing carriage together away from the roll stand such that the lower backup roll of the old set of backup rolls connected to the extraction carriage is brought into a changing position to the side of the roll stand; placing a dummy on the lower backup roll; moving, by the changing cylinder, the roll-changing carriage with the extraction carriage and the lower backup roll of the old set of backup rolls with the dummy back into the roll stand; placing the upper backup roll of the old set of backup rolls on the dummy; moving, by the changing cylinder, the roll-changing carriage with the extraction carriage and the old set of backup rolls out of the roll stand and into the changing position; disconnecting the extraction carriage from the lower backup roll of the old set of backup rolls; replacing the old set of backup rolls with a new set of backup rolls including a dummy; connecting the extraction carriage with a lower backup roll of the new set of backup rolls; moving, by the changing cylinder, the roll-changing carriage with the extraction carriage and the new set of backup rolls into the roll stand; removing the upper backup roll of the new set of backup rolls from the dummy and installing the upper backup roll of the new set of backup rolls in the roll stand; moving, by the changing cylinder, the roll-changing carriage with the extraction carriage and the lower backup roll of the new set of backup rolls with the dummy from the roll stand to the changing position; removing the dummy from the lower backup roll of the new set of backup rolls; moving, by the changing cylinder, the roll-changing carriage with the extraction carriage and the lower backup roll of the new set of backup rolls into the roll stand; disconnecting the extraction carriage from the lower backup roll of the new set of backup rolls; and moving, by the changing cylinder, the extraction carriage and the roll-changing carriage to the distal standby position. 